Google AppEngine App Settings

This package provies a straightforward way to store and access environment-specific and secret/private variables in the Google App Engine Datastore.

Quick start

Install gae_app_settings:

$ pip install gae_app_settings

In your settings module or some other module that loads at startup:

from gae_app_settings import AppSetting
value = AppSetting.get('MY_SETTING_KEY', DEFAULT_VALUE)

Full documentation

AppSetting is a class that is used to persist/store sensitive values in your environment. It is designed to work just like a dictionary, but it is limited to just string values.

Settings cannot be set programmatically, they are only retrievable:

value = AppSetting.get('MY_SETTING_KEY', DEFAULT_VALUE)

NOTE: regardless of the type of DEFAULT_VALUE , value will always be a string. This is to ensure that the return value is of the same type whether the setting is set or unset, as a set value will be a string.

You can also retrieve values without passing a default:

value = AppSetting.get('MY_SETTING_KEY')

Note: If no default value is provided and the key has not been given a value in the datastore, the get() call will raise a KeyError and a placeholder entry will be created in the datastore. Once the placeholder has been replaced with a value future calls to get() will succeed.

Best practices

The following best practices are recommended:

1. Settings should be loaded at program start and stored locally in a settings.py or similar module
2. Default values should be provided for every setting:
   1. these should be the values that make sense when running/testing locally
   2. placeholders will be inserted into the Datastore, and these only need to be overwritten if there are environment-specific settings that need to be set (in production, all values should be set)
3. Do not change the type of the value property in the datastore; coersion should happen on the result of the call to get()